Powertrain OBD System Check

IMPORTANT: Understanding the table and using the table correctly will reduce diagnostic time and prevent the unnecessary replacement of parts.

After the visual inspection is complete, the Powertrain OBD System Check should be performed. The Powertrain OBD System Check is designed as a master table for any driveability and emissions system diagnoses. The Powertrain OBD System Check must always be the starting point for all powertrain system diagnoses. The Powertrain OBD System Check provides a logical step by step process for diagnosing the following areas:
^ An inoperative or damaged PCM, no PCM data, or an inoperative Malfunction Indicator Lamp (MIL).
^ Any PCM Diagnostic Trouble Codes (DTCs)
^ Any customer complaints or driveability symptoms. Any driver comments normally fall into one of the following areas:
^ The MIL is, or was, illuminated.
^ A driveability problem exists.
^ The engine will not start or stalls after starting
^ The vehicle failed an emissions test.
^ A component that the PCM controls is inoperative.